Year	Percent
1998-01-01	25.0552910799455
1999-01-01	25.6766536164979
2000-01-01	26.4133672045543
2001-01-01	27.3530442177535
2002-01-01	27.8967600748184
2003-01-01	28.3303279019951
2004-01-01	29.6596347601073
2005-01-01	29.5299673340982
2006-01-01	30.1326904430724
2007-01-01	30.2959027328056
2008-01-01	30.6389101255702
2009-01-01	30.0788393002111
2010-01-01	29.9255966194944
2011-01-01	30.1334094128218
2012-01-01	30.3982565930468
2013-01-01	29.9222542411321